Depositional and tectono-metamorphic evolution of Trinty Peninsula and Botany Bay Groups, Antarctica, and its role in the Gondwana Supercontinent history

• Grant number: 09/08269-3
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2009
• End date: July 31, 2012
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Renato de Moraes
• Grantee: Renato de Moraes
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The formation of Antarctic Peninsula is related to Gondwana break-up. The rocks that compose the peninsula are related to a fore-arc basin, island arc and a back arc basin system, which was installed in a continental crust in the Gondwana pacific coast, between Triassic and Jurassic. The turbiditic sediments were deposited in an accretionary prism and are now represent by the rocks of the Trinity Peninsula Group, which cover most of northern portion of the peninsula and worked, partially, as basement for plutonic rocks of the island arc. Portions of this group were subducted during Jurassic and are part of Scotia Metamorphic Complex that crops out in the South Orkney archipelago. Not only the rocks of the metamorphic complex are correlated to the ones of Trinity Peninsula Group, the Miers Bluff and Greywacke-shale Formations are also correlated, however some recent works have questioned this relationship. Rocks of the Botany Bay Group, non-marine conglomeratic assemblage, deposited during Jurassic, record the initial rifting stages of Gondwana break-up and rocks of Trinity Peninsula Group worked as source. This proposal has four subjects: 1) the study of petrofacies and provenance of Trinity Peninsula Group rocks, as well as of their correlate units; 2) investigation of tectono-metamorphic evolution of rocks of the Scotia Metamorphic Complex in the Coronation and Powell Islands, South Orkney archipelago; 3) the study of petrofacies and provenance of Botany Bay Group rocks, as well as of their correlate units and; 4) integration of the results of the previous parts with the Mesozoic Gondwana pacific coast history. (AU)